Influence of passive, diet-based, hydration on muscle quantity assessment

Area of Science:

• Physiology
• Body Composition Analysis

Background:

• Hydration status is a critical factor influencing physiological measurements.
• Understanding its impact on lean tissue mass (LTM) and muscle morphology is essential for accurate body composition assessment.

Purpose of the Study:

• To investigate the effects of passive hydration changes on LTM and muscle morphology.
• To determine if hydration status influences measurements obtained via dual-energy X-ray absorptiometry (DXA) and 3D ultrasound.

Main Methods:

• Sixteen healthy participants underwent two testing sessions with manipulated hydration levels (non-hydrated vs. hydrated).
• Measurements included DXA for LTM, 3D ultrasound for vastus lateralis (VL) muscle morphology, and bioelectrical impedance analysis (BIA) for total body water.

Main Results:

• Hydrated participants showed significantly higher total body water (BIA) compared to non-hydrated participants.
• Total LTM (DXA) was significantly higher in the full body and trunk for the hydrated condition.
• Muscle morphology (VL volume and CSA) and limb LTM measurements were not significantly affected by hydration status.

Conclusions:

• Minor passive hydration changes may not significantly alter muscle morphology or limb LTM measurements.
• Total LTM measurements can be influenced by water intake and trunk hydration, potentially biasing muscle mass monitoring.
• Standardizing hydration is recommended when using total LTM to track changes in muscle quantity.